The Radioimmunoassay and Ligand preparation Core is a service core of the University of Virginia Diabetes Research and Training Center. It currently provides about twenty different assays or services to over forty investigators. Assays presently available include total and free serum insulin, insulin C-peptide, glucagon, cyclic AMP, and cyclic GMP radioimmunoassays; hemoglobin A, C, glucose and Lowry protein assays. In addition, (gamma 32 P) - ATP, 125 I cyclic AMP1 ligand, 125 I - peptide and proteins are produced by the core facility. We also offer and assist with HPLC techniques for separations, purifications, and analysis. Computational facilities for data from gamma counting and radioimmunoassays (tape reader, computer, printer/plotter) represent an important service of this Core. This application requests continued support for the various services provided to investigators by the Core. Critical evaluation and quality control of current services and the development of improved and/or new analytical techniques and methodologies desired by investigators (as directed by the Executive Committee) represent other benefits derived from this facility. Objectives: 1. To provide assays, reagents, radio labeled ligands, and services to DRTC Members. 2. To assist and advise on labeling, radioimmunoassay, labeled ligand preparation, and HPLC technological methods to DRTC members. 3. To assist in data calculation and evaluation. 4. To develop new analytical methods, reagents, and techniques as required by DRTC members. 5. To teach existing and new techniques to DRTC members as required.